ATE refers to an automated, usually computer-driven, system for testing devices, such as semiconductors, electronic circuits, and printed circuit board assemblies. A device tested by ATE is referred to as a device under test (DUT).
ATE typically includes a computer system and a testing device or a single device having corresponding functionality. ATE is capable of providing test signals to a DUT, receiving response signals from the DUT, and forwarding those response signals for processing to determine whether the DUT meets testing qualifications.
Calibration can affect the performance of ATE. For example, ATE may be calibrated to achieve timing accuracy. In ATE, timing accuracy includes, among other things, applying signals to a DUT that meet predefined timing constraints. For example, the rising edge of a signal may need to reach the DUT within a specified time-frame in order to test the DUT accurately. As the operational speeds of DUTs increase, timing accuracy becomes more critical, since there is typically less tolerance for signal time variations during testing.
Typically, timing deskew calibration (e.g., alignment of signal timing between tester channels) uses either time domain reflectometry (TDR) which may include sending a pulse into a channel and looking for a reflection, or a robotic calibration at the tester interface combined with off-line measurement of delay through a load board. Both methods suffer from measurement errors that make it difficult to achieve skews in the picosecond range. This is because, in both methods, the timing measurement is not done where the DUT is located during test time, e.g., in the DUT socket. Some types of calibration use probing at the socket landing pattern, but this typically requires removal of the socket before each calibration, which is time consuming and can wear out the load board, and still does not necessarily achieve timing where the DUT resides. This also requires external equipment such as probes, cables, test instruments, etc.